The phrase "copy number" refers to the number of times a particular gene or DNA sequence is repeated in a cell's genetic material. It tells us how many duplicates of that specific DNA segment are present. Full definition
The number and extent of copy number alterations, too, followed this trend. (massgenomics.org)
The researchers are analyzing more patient samples looking for additional cases of multiple copy number variants to continue their investigation of what may trigger this rare phenomenon. (sciencedaily.com)
In other words, acquired copy number alterations influence the expression of genes within them or nearby. (massgenomics.org)